Mob rules, with advantage.

[viaFAMILIAR]

Would having advantage on attacks affect the numbers on the mob rules chart? I couldn't find anything in the 5e manuals. I'd say increase the odds by one step on the chart.

Any thoughts on this matter?

[NaughtyTiger]

Would having advantage on attacks affect the numbers on the mob rules chart? I couldn't find anything in the 5e manuals. I'd say increase the odds by one step on the chart.

Any thoughts on this matter?

advantage is typically treated as a +5 to passive abilities.

this is how i have been running mob rules for conjure beasts...

[Man_Over_Game]

advantage is typically treated as a +5 to passive abilities.

this is how i have been running mob rules for conjure beasts...

Advantage/Disadvantage is probably closer to a 3.33 change when considering the non-average outcomes (1 and 20, rather than 10 or 11). Even when comparing Advantage and Disadvantage when it's the biggest deal (which is when comparing a die roll of 10), it only provides about a 4.5 point difference. Even though 3.33 is the accurate average, it's unlikely that a 2, 3, or 19 will ever be relevant, as most rolls only need somewhere between a 7 and a 16 to be a success.

Or, put into layman's terms:

Real Change from Dis/Advantage: -/+ 3.33
Realistic Change from Dis/Advantage: -/+ 4.00

Wizards of the Coast probably just used the -/+ 5.00 to keep things simple.


As for the question at hand, this RPG Stack Exchange question has a decent enough answer on the topic: https://rpg.stackexchange.com/questions/103229/how-does-the-handling-mobs-rule-work-with-advantage-disadvantage
Basically, if you counted it as a -/+5, then it'd dramatically impact creatures that have a low hit chance, and creatures with high hit chance would barely be impacted.

[NaughtyTiger]

snip

I am grabbing my answer based on the PHB, because mob rules are the equivalent of passive attack rolls...
"that creature's passive Wisdom (Perception) score, which equals 10 + the creature's Wisdom modifier, as well as any other bonuses or penalties. If the creature has advantage, add 5. For disadvantage, subtract 5."

I assume that you would also change the values for observant, alert, and any passive rolls to 3.33 instead of 5?

[Man_Over_Game]

you reference the 3.33 often. how are you calculating that?

Compare the chances the odds of every potential result (1, 2, 3,...20), of Advantage, Disadvantage, and the classic 1d20.

You'll note that Advantage is, on average, 16.65% higher than the standard 1d20.

For example:

Advantage 2+: 99.75%
Normal 2+: 95%

Difference: 4.75% (roughly +1 in value)

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Advantage 10+: 79.75%
Normal 10+: 55%

Difference: 24.75% (Roughly +5 in value)

------------

Advantage 20: 9.75%
Normal 20: 5%

Difference: 4.75% (roughly +1 in value)

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If you average the differences up (of all the odds of every possible result, 1-20), you end up with +16.65% on Advantage, which translates into roughly a +3.33 bonus on a D20 (as each side is 5%).

Disadvantage is the exact same, except as a -3.33.

The thing is, though, that 3.33 is counting the absolutes as part of the equation, but...they generally don't matter. Rarely will you miss if your attack is over 15, and rarely will you hit if you rolled under a 5. Most rolls where Dis/Advantage matter will rely on you rolling somewhere between the values of 7 and 16. If you only count those numbers, you end up with a value that's closer to 4.00 instead of 3.33.

You can check my observations by using Anydice: https://anydice.com/program/123f